int   mult_add_fix8bx4 (char a0_in, char b0_in, char a1_in, char b1_in, char a2_in, char b2_in, char a3_in, char b3_in) {return (a0_in*b0_in)+(a1_in*b1_in)+(a2_in*b2_in)+(a3_in*b3_in);}